We have a bride here on Hwy 5 in Nebraska.  Built in about 1976. The state has been out there many, many times over the years with man lifts looking at the bottom, teams putting sensors on it and watching it for days, you name it they have tested for it I think.  It is a bridge that is what I call all steel. What you drive over is steel iron on edge and it makes a rumble sound as you drive over.  No concrete.  Everything falls right through.  Do not remember seeing another one like it. 

Anyway, after years of study, they have put up weight restriction signs for the bridge.  No longer can 80,000 trucks use this bridge.  LOL. Hundreds of not thousands of such trucks still go over that bridge yearly.  No one I know of has ever gotten a ticket.  Signs have been up for maybe 2 years now.  Prob. put on their bridge replacement schedule for the year 2052.  LOL.

A neighbor who lives right by the bridge stopped and talked.  Yes, he was told that the bridge would be unsafe if 2- 80,000 were on the bridge at the same time.